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International journal of sport biomechanics最新文献

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A Mathematical Model of Competitive Swimming in Pools with Currents 有水流池中竞技游泳的数学模型
International journal of sport biomechanics Pub Date : 1991-05-01 DOI: 10.1123/IJSB.7.2.163
R. Hinrichs, S. McLean
{"title":"A Mathematical Model of Competitive Swimming in Pools with Currents","authors":"R. Hinrichs, S. McLean","doi":"10.1123/IJSB.7.2.163","DOIUrl":"https://doi.org/10.1123/IJSB.7.2.163","url":null,"abstract":"Swimmers may be placed at a disadvantage when water in a pool is actively circulated during competition. This circulation may produce currents in specific lanes which add to a swimmer’s speed in one direction and subtract from it in the other direction. This article presents a mathematical model of swimming in a lane with a current. It predicts that even small currents can add significantly to a swimmer’s race time. The effects of the current will not equal out over an even number of lengths swum because the swimmer always loses more time swimming against the current than he or she gains from swimming with the current. Mathematical simulations of races of various distances show that the losses in time can range from 100ths of a second in a 100-m sprint to several seconds in the longer distances. Since circulating water may create currents only in specific lanes, some swimmers may be placed at a disadvantage compared to others. A simple solution to the problem of currents is suggested.","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123965683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
MUSCLE SORENESS DURING RUNNING - BIOMECHANICAL AND PHYSIOLOGICAL CONSIDERATIONS 跑步时的肌肉酸痛——生物力学和生理学的考虑
International journal of sport biomechanics Pub Date : 1991-05-01 DOI: 10.1123/IJSB.7.2.125
J. Hamill, P. Freedson, P. Clarkson, B. Braun
{"title":"MUSCLE SORENESS DURING RUNNING - BIOMECHANICAL AND PHYSIOLOGICAL CONSIDERATIONS","authors":"J. Hamill, P. Freedson, P. Clarkson, B. Braun","doi":"10.1123/IJSB.7.2.125","DOIUrl":"https://doi.org/10.1123/IJSB.7.2.125","url":null,"abstract":"This study involved an 8-day protocol to determine the effects of delayed-onset muscle soreness (DOMS) on the mechanics of the lower extremity and on oxygen consumption during level running. On Day 1 the subjects, 10 healthy female recreational runners, were administered a treadmill max VO2 test. They completed a 30-min downhill run on Day 3 to induce muscle soreness. On Days 2, 5, and 8 they completed a 15-min level run at a speed corresponding to 80% of VO2max. Subsequent to each run the subjects completed a muscle soreness questionnaire and a blood sample was taken for creatine kinase (CK) analysis. Data analysis revealed statistically significant between-day differences for perceived muscle soreness and CK activity. However, metabolic cost was not different between days. There were significant differences between days in maximum ankle support dorsiflexion and plantar flexion and maximum knee flexion during both support and swing. None of the global parameters describing the total stride produced sig...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"185 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114372845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 65
Changes in Distance Running Kinematics with Fatigue 疲劳对长跑运动学的影响
International journal of sport biomechanics Pub Date : 1991-05-01 DOI: 10.1123/IJSB.7.2.138
K. R. Williams, R. E. Snow, C. Agruss
{"title":"Changes in Distance Running Kinematics with Fatigue","authors":"K. R. Williams, R. E. Snow, C. Agruss","doi":"10.1123/IJSB.7.2.138","DOIUrl":"https://doi.org/10.1123/IJSB.7.2.138","url":null,"abstract":"This study investigated changes in kinematics with fatigue during intercollegiate competition, a noncompetitive track run, and a constant speed treadmill run. To account for changes in kinematics resulting from speed differences, regression equations for each individual generated from nonfatigue data were used to predict rested kinematics for speeds matching those of the fatigue conditions. A factor analysis procedure grouped 29 kinematic variables into sets of independent factors, and both factor variables and individual variables were analyzed for changes with fatigue, which were minimal. Only one significant difference was found in the factor variables between nonfatigue and fatigue states. Comparisons of specific kinematic variables showed a significant increase in step length with fatigue, an increased maximal knee flexion angle during swing, and an increased maximal thigh angle during hip flexion. While fatigue did not result in marked changes in kinematics for the group as a whole, changes for indi...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"213 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117320116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 96
Electromyographic Analysis of Muscle Activation during Ski Jumping Performance 跳台滑雪运动中肌肉活动的肌电图分析
International journal of sport biomechanics Pub Date : 1991-05-01 DOI: 10.1123/IJSB.7.2.175
M. Virmavirta, P. Komi
{"title":"Electromyographic Analysis of Muscle Activation during Ski Jumping Performance","authors":"M. Virmavirta, P. Komi","doi":"10.1123/IJSB.7.2.175","DOIUrl":"https://doi.org/10.1123/IJSB.7.2.175","url":null,"abstract":"Electromyographic (EMG) activities of gluteus maximus (GL), vastus later-alis (VL), vastus medialis (VM), tibialis anterior (TA), and gastrocnemius (GA) were measured telemetrically from four world-class athletes during the entire ski jumping performance. Integrated electromyographic activities (IEMG) were calculated from the different phases of jump. TA and GA showed alternate activation during the curve, suggesting that maintenance of the inrun position is a process requiring continuous active control. VL and VM were observed to contribute mostly to the entire takeoff phase whereas GL became strongly active within the last 4 meters of the takeoff. GA was slightly but continuously active during the inrun and showed only a small increase during takeoff. The quick lifting of the skis, as evidenced by the activation of TA, does not seem to allow effective use of GA at the end of the takeoff. Strong continuous activity of the knee extensors and TA dominated the midflight phase whereas the activation of GL an...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127049072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 14
Kinematics and Impulse Characteristics of Drop Landings from Three Heights 三高度落体的运动学和冲量特性
International journal of sport biomechanics Pub Date : 1991-05-01 DOI: 10.1123/IJSB.7.2.201
J. McNitt-Gray
{"title":"Kinematics and Impulse Characteristics of Drop Landings from Three Heights","authors":"J. McNitt-Gray","doi":"10.1123/IJSB.7.2.201","DOIUrl":"https://doi.org/10.1123/IJSB.7.2.201","url":null,"abstract":"During a landing impact, the human body is exposed to large forces and moments that create the potential for injury. To determine the effect of impact velocity and landing experience on the strategy selected, the preferred landing strategies used by male collegiate gymnasts and recreational athletes from three drop heights were characterized using mechanical descriptors. Kinematic and reaction force data were acquired simultaneously using highspeed film and a force plate. Reaction forces and lower extremity joint motion were used to characterize the strategies. Results indicated that statistically significant increases in joint flexion (with the exception of ankle joint flexion), angular velocity, and impact force resulted as impact velocity increased. Gymnasts and recreational athletes demonstrated similar adjustment patterns to increases in landing impact velocities; however, significant differences in degree of joint flexion, total landing phase time, and relative adjustments over impact velocity condi...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131056914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 233
A Biomechanical Comparison of the Yurchenko Vault and Two Associated Teaching Drills 尤尔琴科跳马的生物力学比较和两个相关的教学练习
International journal of sport biomechanics Pub Date : 1991-02-01 DOI: 10.1123/IJSB.7.1.91
B. Elliott, Joanne Mitchell
{"title":"A Biomechanical Comparison of the Yurchenko Vault and Two Associated Teaching Drills","authors":"B. Elliott, Joanne Mitchell","doi":"10.1123/IJSB.7.1.91","DOIUrl":"https://doi.org/10.1123/IJSB.7.1.91","url":null,"abstract":"Two-dimensional high-speed photography was used to compare the performances of six elite gymnasts on a Yurchenko vault and two associated teaching drills. Analysis of variance with repeated measures was used to test the significance of the differences between those variables common to both drills and the vault, while a one-way analysis of variance was used to test for differences between biomechanical variables common to only one drill and the vault. Results indicated that in general the variables common to each drill and the vault were similar in magnitude. However, a number of kinematic characteristics recorded in the drills differed from those recorded for the vault both in this study and from data reported in the literature for international level performers. These included horizontal velocity at takeoff from beat board; knee joint, lower trunk, midtrunk, and head/neck segments at takeoff from beat board; knee joint angle and vertical velocity of CG at impact with horse; vertical velocity, trunk angle...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128771413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 24
A Comparison of Maximal Power Outputs between Elite Male and Female Weightlifters in Competition 优秀男女举重运动员在比赛中最大输出功率的比较
International journal of sport biomechanics Pub Date : 1991-02-01 DOI: 10.1123/IJSB.7.1.3
J. Garhammer
{"title":"A Comparison of Maximal Power Outputs between Elite Male and Female Weightlifters in Competition","authors":"J. Garhammer","doi":"10.1123/IJSB.7.1.3","DOIUrl":"https://doi.org/10.1123/IJSB.7.1.3","url":null,"abstract":"Films taken at the first Women’s World Weightlifting Championship were analyzed to determine the average power output during the total pulling phase, and the second pull phase, for the heaviest successful snatch and clean lift of gold medalists in each of nine body-weight divisions. Comparisons were made with previously published data on power output by male lifters in World and Olympic competition. Average relative power output values were one and a half to two times greater for both men and women when only the second pull phase of each lift was analyzed. Results show that women can generate higher short-term power outputs than previously documented, but lower than for men in absolute values and relative to body mass. Male/female comparisons in other high power sport events and basic strength measures are discussed. The high power outputs suggest the value of including the types of lifts analyzed in training programs to improve short-term power output.","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121519709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 116
A Comparison of Techniques Used in Performing the Men’s Compulsory Gymnastic Vault at the 1988 Olympics 1988年奥运会男子跳马项目技术比较
International journal of sport biomechanics Pub Date : 1991-02-01 DOI: 10.1123/IJSB.7.1.54
Y. Takei
{"title":"A Comparison of Techniques Used in Performing the Men’s Compulsory Gymnastic Vault at the 1988 Olympics","authors":"Y. Takei","doi":"10.1123/IJSB.7.1.54","DOIUrl":"https://doi.org/10.1123/IJSB.7.1.54","url":null,"abstract":"It was hypothesized that the techniques employed by two groups of male gymnasts in performing the handspring and salto forward tucked vault at the 1988 Olympics were not significantly different. The 11 highest scored vaults (Gl) of the 51 subjects filmed during the competition were compared with the 11 lowest scored vaults (G2). The G1 had (a) significantly greater horizontal velocity of hurdle and preflight and (b) significantly greater vertical reaction forces exerted on them by the horse, which in turn produced a significantly greater change of vertical velocity while on horse. Consequently, the better gymnasts departed from the horse with significantly greater vertical velocity, which resulted in significantly greater height, larger distance, and longer time of postflight than the gymnasts in G2. The better gymnasts had the instant of the tightest tuck position while significantly nearer the instant of peak postflight than the G2 gymnasts, which caused the height of CG at the tightest tuck position to...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115460040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 32
Changes in Distance Running Mechanics Due to Systematic Variations in Running Style 跑步方式系统性变化导致的长跑力学变化
International journal of sport biomechanics Pub Date : 1991-02-01 DOI: 10.1123/IJSB.7.1.76
K. R. Williams, J. L. Ziff
{"title":"Changes in Distance Running Mechanics Due to Systematic Variations in Running Style","authors":"K. R. Williams, J. L. Ziff","doi":"10.1123/IJSB.7.1.76","DOIUrl":"https://doi.org/10.1123/IJSB.7.1.76","url":null,"abstract":"There is little information on how a change in one feature of an individual’s running mechanics affects other aspects of running style. This study manipulated experimental conditions such that eight subjects ran with three different step lengths, three step widths, and three varying degrees of shoulder rotation. The effect of these changes on rearfoot pronation measures, step length, and step width were examined. Results showed that varying step length over a range of 18 cm and shoulder rotation over a range of 17° caused no significant differences in maximal pronation angle, total amount of pronation, or maximal pronation velocity. Varying step width from landing approximately 5 cm lateral to the midline to crossing over a midline by 2 cm increased the maximum pronation from 12.2 to 18.3°, the amount of pronation from 14.1 to 21.1°, and maximal pronation velocity from. 329°/s to 535°/s. It is suggested that runners with problems due to excessive pronation might try changing step width. Changes in step wi...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131479016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 21
The Pedaling Technique of Elite Endurance Cyclists: Changes with Increasing Workload at Constant Cadence 优秀耐力自行车运动员的蹬车技术:在恒定节奏下随负荷增加而变化
International journal of sport biomechanics Pub Date : 1991-02-01 DOI: 10.1123/IJSB.7.1.29
S. Kautz, M. E. Feltner, E. Coyle, A. Baylor
{"title":"The Pedaling Technique of Elite Endurance Cyclists: Changes with Increasing Workload at Constant Cadence","authors":"S. Kautz, M. E. Feltner, E. Coyle, A. Baylor","doi":"10.1123/IJSB.7.1.29","DOIUrl":"https://doi.org/10.1123/IJSB.7.1.29","url":null,"abstract":"A pedal dynamometer recorded changes in pedaling technique (normal and tangential components of the applied force, crank orientation, and pedal orientation) of 14 elite male 40-km time trialists who rode at constant cadence as the workload increased from similar to an easy training ride to similar to a 40-km competition. There were two techniques for adapting to increased workload. Seven subjects showed no changes in pedal orientation, and predominantly increased the vertical component of the applied force during the downstroke as the workload increased. In addition to increasing the vertical component during the downstroke, the other subjects also increased the toe up rotation of the pedal throughout the downstroke and increased the horizontal component between 0° and 90°. A second finding was that negative torque about the bottom bracket during the upstroke usually became positive (propulsive) torque at the high workload. However, while torque during the upstroke did reduce the total positive work requi...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"769 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123279912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 78
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